Re: Bendix Treadle Vac Study- Serioius Business!!

Posted by HH56 On 2011/1/3 11:42:10

It appears to be Buicks version or copy of the Treadlvac. They had one version in 53-4 and then a different power unit design in 55-56.

There is also a Moraine variant of the Treadlvac with some differences in both sections used in some mid 50's cars. It is interesting that so many cars used similar units. I've always been curious why one unit seems to be used partial years here or there or in this model or that. There seems like a lot of interchange or switching across the full line and even full year.

All are similar in that they use the ram type hydraulic section instead of the piston/cup and differ mostly in the seals and vacuum section. There are a lot of variations in that vacuum section thru the years. The 55-6 Buick unit appears similar in vacuum design to the later hydraulic reaction Treadlevac units.

If you have access to the old Motors Auto Repair Manual, the 20th edition covers all of them in some detail with illustrations.